The Detachable Thumb

Lesson overview

Materials

Substitutes: Nothing needed — you are the prop. All you need is two hands and someone standing in front of you.

Before you begin

1. 1

   Find a mirror

   This trick is entirely about what it looks like from the front. Learn it in a mirror or with your phone camera propped up.

2. 2

   Warm up your thumbs

   Bend both thumbs down at the base a few times. Stiff thumbs will not fold flat enough to disappear.

3. 3

   Plan your position

   Decide where your audience will be. Straight in front of you, at roughly your own eye level, is the only safe arrangement.

Environment: Perform with your audience directly in front of you and nobody at your sides or looking down from above. This is the most angle-sensitive trick a beginner will ever learn. A mirror — or your phone camera propped up — shows you exactly what your audience will see.

Performance script

A sample script to adapt — make it your own, and never rush the pauses.

• (Hold up the left thumb and wiggle it.) "Standard thumb. Came with the hand. Two owners, low mileage."
• (Grip it.) "The thing about thumbs is that nobody ever checks whether they're bolted on..."
• (Slide, hold the gap.) "...and mine, unfortunately, are not."
• (Slide back, wiggle.) "Back on. Good as new. Don't try this — yours are probably the permanent kind."

Performance tips

• Perform face-on only, with nobody at your sides. Angles are the whole vulnerability of this trick.
• Keep the gap small — two centimetres reads as impossible, four reads as two hands.
• Hold the gap for two full seconds. The pause is where the reaction lives.
• React to your own thumb: a wince or a worried look tells children exactly how to feel about it.
• Do it once and stop. A second showing invites a child to walk round and look from the side.

Common mistakes

• Letting the right index finger slip so the join between the two thumbs is visible.

  Fix: Drill the slide with your eyes on that finger. It must cover the seam for the entire movement.

• Sliding the thumb too far, so the picture obviously becomes two separate hands.

  Fix: Limit the slide to about two centimetres and hold there. Small is more convincing.

• Rotating the left hand toward the audience and exposing the folded thumb.

  Fix: Keep the back of the left hand square to the front and turn your whole body if you need to face someone else.

• Racing through the separation with no pause at the gap.

  Fix: Stop at the gap and silently count two seconds before sliding back.

• Building the thumb position slowly and visibly before starting.

  Fix: Fold the left thumb only as the right hand moves in, so the setup is covered by the approach.